The Villigen Formation is dominated by limestone and shows relatively low variability (Fig. 4‑51). Lateral correlation of calcareous successions can be guided by marker beds such as the «Knollen Bed», which, however, could not be identified in all boreholes. Occurrence of sponges, especially in the Hornbuck Member, may lead to lateral and vertical variability as they can form bioherms of very local extent.

The Schwarzbach Formation shows relatively low variability and can be laterally well correlated (Fig. 4‑51). Additionally, the general succession of more calcareous to argillaceous beds within the Schwarzbach Formation seems to be correlatable, especially in the boreholes of NL.

The facies units of the «Felsenkalke» and «Massenkalk», interfinger laterally and vertically, but both facies units are dominated by limestones. The sponge bioherms of the «Massenkalk» probably formed mounds that were surrounded by the well-bedded «Felsenkalke». These mounds can have lateral extents of few decametres to several kilometres (Geyer et al. 2023). Additionally, beds particularly enriched in fossils and glauconite exist. One of these beds, the «Glauconitic Marker Bed», was identified as a marker horizon by Gygi (2000a).